Fuse for projectiles



A ril 24, 1934. N. E. METHLIN FUSE FOR PROJECTILES Filed Feb. 23, 1933 3 Sheets-Sheet 1 April 24, 1934. N. E. METHLIN FUSE FOR PROJECTILES Filed Feb. 25, 1933 3 Sheets-Sheet 2 awe/M3011 April 24, 1934.. METHLlN 1,956,222

FUSE FOR PROJECTILES Filed Feb. 23, 1953 5 Sheets-Sheet 3 C 1' x YII m Z\ a i z m x Z jg 7' 7 .1; '1 .7 I

WW MWQ M Patented Apr. 24, 1934 FUSE FOR PROJECTILES Nicolas Emilien Methlin, Paris, France, assignor to Schneider & Cie., Paris, France, a company of France Application February 23, 1933, Serial No. 658,186 In France December 20, 1932 4 Claims.

The present invention relates to a percussion fuse of the type adapted to operate by the driving in of the front element and the inertia of the rear element, or solely by the driving in of the front element, the said fuse comprising, between the fixed or movable percussion cap and a striker which constitutes the front element of the mechanism and is fixed to the fuse body by a pin, a

stop member adapted to be rendered inoperative or to be ejected under the action of the centrifugal force, or under the action of the gases of a striking device operative on the firing of the shot.

The new fuse is characterized in that the safety member, which is automatically rendered inop- 5 erative after the firing of the shot, is disposed at a very small distance from a shoulder provided on the striker fixed to the fuse body by a pin, the said distance being such that on the firing of the shot, the striker, under the action of its inertia, is able to execute an inward movement of an amplitude small enough to obviate rupture of the pin, but yet sufiicient to weaken the said pin. Under such conditions the pin may be made of an appropriate strength in regard to the handling of the projectile and to the stresses to which the fuse is subjected during transport, the said strength being reduced on the firing of the shot to the desired extent for conferring upon the mechanism considerable sensitivity in operation at the point of impact.

Various constructional examples of the invention are shown in the accompanying drawings, wherein like reference characters indicate like parts throughout the several views:

Figure 1 is a longitudinal sectional elevation of one form of fuse embodying the present invention, the parts thereof being shown in their at rest position;

Figure 2 is a similar view of the fuse of Figure 1 showing the parts in the position they occupy during the period of acceleration;

Figures 3-5 are views similar to Figure 1 of another form of fuse embodying the invention, the movable members of the mechanism being shown in these figures in the positions which they occupy when at rest, during the period of acceleration, and when the fuse is armed, respectively;

Figure 6 is a View similar to Figure 1 of still 50 another embodiment of the invention; and

Figure '7 is a cross sectional view taken substantially on line VII-VII of Figure 6.

In Figures 1 and 2, a and a denote the elements of the fuse body. The element a of the said 55 fuse body has a striker b fixed to it by means of a pin 0. The percussion cap carrier mi -a is fixed in the element a The known percussion mechanism of the fuse operates in this example exclusively by the driving in of the front element and is combined with a safety device which, in this instance, is adapted to be rendered inoperative under the action of the centrifugal force. The said safety device may be constituted in the manner known per se by segments c which are normally held around the striker by a flexible connection e and which are disposed in a recess of the fuse body, so that, after the period of acceleration, they are able to move completely apart within the said recess for releasing the striker, the latter being then retained by the pin alone.

According to the invention, a distance at is pro vided between a shoulder 19 of the striker or striker carrier and the safety device or an element of the said safety device, the said distance a: being fairly small but yet sufficient for the inward course permitted to the striker under the action of inertia on the firing of the shot to be such that the pin, which is subjected to the force of inertia of the striker, commences to be sheared, as shown in an exaggerated manner in Figure 2.

At the end of the period of acceleration, the segments e move completely apart while opening the flexible connection 6 which held them together. The striker, although it has made an inward movement corresponding at a maximum to the distance x, nevertheless remains at an appropriate distance from the percussion cap (1 until the moment an obstacle is encountered.

The pin 0, however, is rather considerably weakened. Its strength has been diminished, which increases the sensitivity of the mechanism in regard to its operation at the point of impact.

Of course, even after the segments have been rendered inoperative, the pin should retain a suitable strength, so that it cannot rupture under the effect of the air pressure exerted on the head of the striker.

In Figures 3-5, the invention is applied to a type of fuse according to the prior French Patent No. 637,643 and British Patent No. 280,859, of the 17th November 1926, of the applicant, the said fuse being adapted to operate either by the driving in of the front element or by the driving in of the front element and the inertia of the rear element. The mechanism comprises a striker (front element) b, provided with a shoulder 19 and normally fixed to the element a of the fuse body by a pin c. The rear element is constituted by a percussion cap carrier plunger (d -d), held at a distance from the striker by a spring I. This mechanism is combined with a safety device of known type comprising segments e held by a flexible connection e in a groove of the percussion cap carrier plunger (1 A sleeve g bears with its rear edge on the said segments, the said sleeve being subjected to the action of a spring h bearing with its front end either on the element a of the fuse body or preferably on a counter sleeve 1' which, in the known manner, constituted a safety device for preventing the segments from moving apart during the period of acceleration.

According to the invention, a clearance m is left between the shoulder 11 of the striker and the front edge of the sleeve g. 1

Normally, the members occupy the position shown in Figure 3. The inertia of the striker is utilized, as shown in Figure 4, to cause this front element of the mechanism to move inwardly over the distance x, the shoulder b once its travel has been completed, bearing against the front edge of the sleeve g. In this movement, the pine undergoes a commencement of shearing.

The acceleration being terminated, the counter sleeve i which, under the action of its inertia, has been brought into the position shown in Figure 4 while compressing the spring h, is urged forwardly. When, on occupying the position shown in Figure 5, it has released the segments, the latter move apart and bear against the inner wall of the element a of the fuse body. The sleeve g is then driven to the rear by the spring h into the position shown in Figure 5, in which it prevents any accidental return of the segments 6. The fuse is then armed. It is operated by the driving in of the front element and by inertia of the rear element during stoppage or retardation of the movement of theprojectile on contact with an obstacle, and, as in the preceding example, the sensitivity of the mechanism is increased by the diminution in the strength of the pin 0.

Figures 6 and '7 show an example of the application of, the invention to the type of fuse described by U. S. Letters Patent No. 1,750,723, of the 18th March 1930, of the applicant. This fuse also operates by the driving in of the front element and by inertia of the rear element.

The mechanism comprises, in a fuse body a, a striker b normally fixed to the said fuse body by a pin c, and a percussion cap carrier plunger d d, maintained at the bottom of its seat by a spring 1.

The safety device with which the mechanism is combined comprises a locking bolt y-7' -7' which engages a transverse recess provided in the fuse body a, andwhich is normally fixed by a pin 9' engaging a stud 7' projecting from the bolt head. The upper part of the locking bolt is provided with a flat supportingportion 7' for the striker b when the latter has travelled inwardly, by the distance it. After the firing of the shot, the bolt :1

'is ejected by the means described in the abovementioned prior patent of the applicant. For this purpose, the fuse comprises a striking mech anism, constituted by a fixed striker k which, on the firing of the shot, encounters a movable percussion cap carrier 70 The flame is transmitted to a charge of powder m, the gases of which act upon the stud 7' of the bolt 7'. On the firing of the shot, the striker bb lags behind under the action of its inertia and bears against the fiat part 7' of the bolt 9', the pin a being thus subjected to a shearing stress owing to the forward movement of the projectile. The locking bolt 7 -7 is ejected after rupture of the retaining pin 7' and the fuse is then armed, so that it is capable of operating, on impact, by the driving in ofthe striker b and by the action of the inertia of the percussion cap supporting plunger d d. As in the preceding examples, the operation of the fuse on impact is facilitated, owing to the weakening undergone by the pin 0 in the inward movement of the striker on the firing of the shot.

I claim:-

l. A percussion fuse mechanism for projectiles comprising a fuse body adapted to be secured to a projectile, percussion cap and striker members housed within said fuse body, one of said members being movable relatively to the other and to said fuse body, safety means for positively preventing movement of said movable member into striking position until after the projectile is fired, said safety means being so constructed and arranged as to permit a relatively small movement of said movable member at the instant of firing due to the inertia thereof, and a frangible retainingpin passing through and normally securing said movable member in a fixed position relative to the fuse body, said retaining pin being yieldable without rupture upon said relatively small movement at the instant of firing but rupturable upon impact, said relatively small movement being limited by said safety means to an amplitude such that the resistance of said retaining pin to further movement of said member is decreased below its original resistance to initial movement but is maintained sufiicient to balance the forces exerted thereon incident to normal flight of the F erative after the projectile is in flight but prior to that time positively preventing movement of said striker member into striking position, a shoulder formed on said striker member and normally separated from an abuttable surface of said safety device by a relatively small distance. so as to permit a relatively small movement ofsaid striker member at the instant of firing due tothe inertia thereof, and a frangible retaining pin passing through and normally securing said striker member in a fixed position relative to the fuse body, said retaining pin being yieldable without rupture upon said relatively small movement at the instant of firing but rupturable uponimpact, said relatively small movement being limited by striker member and adapted to be rendered inopabutment of said shoulder against said safety r device to an amplitude such that the resistance of said retaining pin to further movement of said member is decreased below its original resistance to initial movement but is maintained sufficient movement of said striker member into striking position until after the projectile is in flight, a sleeve member movable axially of said fuse mechanism and normally resting at one end on said safety device, a shoulder formed on said striker member and normally separated from the other end of said sleeve member by a relatively small distance so as to permit a relatively small movement of said striker member at the instant of firing due to the inertia thereof, said sleeve member being movable away from said shoulder after said safety device is rendered inoperative during flight of the projectile, and a frangible retaining pin passing through and normally securing said striker member in a fixed position relative to the fuse body, the amplitude of said relatively small movement being limited by engagement between said shoulder and sleeve member to an amount sufiicient to materially weaken the resistance of said retaining pin to further movement of its associated striker member but insufiicient to fracture said element, whereby the sensitivity of the fuse upon impact is increased.

4. A percussion fuse mechanism for projectiles comprising a fuse body adapted to be secured to a projectile, percussion cap and striker members housed Within said fuse body, said striker member being movable relatively to said percussion cap member and to said fuse body, a safety device for positively preventing movement of said striker member into striking position until after the projectile is fired including a stop member movable radially of said fuse body and interposed between said striker and percussion cap members and explosive means for ejecting said stop member from the fuse body after the projectile has commenced its flight, a shoulder formed on said striker member and normally separated from an abuttable surface on said stop member by a relatively small distance so as to permit a relatively small movement of said striker member at the instant of firing due to the inertia thereof, and a frangible retaining pin passing through and normally securing said striker member in a fixed position relative to the fuse body, said retaining pin being yieldable without rupture upon said relatively small movement at the instant of firing but rupturable upon impact, said relatively small movement being limited by engagement be tween said shoulder and abuttable surface to an amplitude such that the resistance of said retaining pin to further movement of said striker member is decreased below its original resistance to initial movement but is maintained suificient to balance the forces exerted thereon incident to normal flight of the projectile, whereby the sensitivity of the fuse mechanism upon impact is increased.

NICOLAS EMILIEN METHLIN. 

